Recently, as the interest in stereoscopic image services is growing, devices for providing stereoscopic images continue to be developed. Among the schemes for implementing such stereoscopic images is a stereoscopic scheme.
A basic principle of the stereoscopic scheme is that images arranged to be perpendicular to the left and right eyes of a person (or a user) are separately input and each image respectively input to the left and right eyes are combined in the user's brain to generate a stereoscopic image. In this case, the arrangement of the images such that they are perpendicular means that the respective images do not interfere with each other.
Methods for preventing interference include a polarization scheme, a time-sequential scheme, and a spectral scheme.
First, the polarization scheme is to separate respective images by using a polarization filter. Namely, the polarization filter perpendicular to an image for the left eye and an image for the right eye is employed to allow different images filtered by the polarization filter to be input to the left and right visual fields. The time-division scheme is that left and right images are alternately displayed and active glasses worn by the user is synchronized with the alternately displayed images to thus separate the respective images. Namely, when the images are alternately displayed, the shutter of the synchronized active glasses opens only the visual field to which a corresponding image is to be input and blocks the other visual field to separately input the left and right images.
Meanwhile, the spectral scheme projects left and right images through a spectral filter having a spectrum band in which RGB spectrums do not overlap with each other. With respect to the thusly projected left and right images, the user wears passive glasses including a spectral filter passing through only a spectral area set for the left and right images, thus separately receiving the left and right images.
However, the related art digital broadcast is based on two-dimensional (2D) images. For example, a PSIP (Program and System Information Protocol) used in the ATSC (Advanced Television Systems Committee) type digital broadcast is targeted only for a 2D image service.
Thus, in order to provide a stereoscopic image in the digital broadcast, a signal for a stereoscopic image in a PSIP used in the existing ATSC type digital broadcast or in SI (Service Information) used in a DVB (Digital Video Broadcasting) type digital broadcast must be checked and processed.
Also, in order to effectively process such stereoscopic image signals in the digital broadcast, a digital broadcast receiving apparatus is required to be configured to be able to receive and process stereoscopic image signals.